Unsure if they need a functional 2nd stage on the test. They could do it like the Apollo program, just a 1st stage. Or just put some weight to simulate the 2nd stage.And I think SpaceX will try to persuade NASA to do a 1st stage recovery some seconds after the LAS test. Depends on how fast Grasshopper evolves.
Could they combine the in-flight abort test with a test of the F9 first stage's ability to propulsively land? I.e. Dragon "punches off" of the F9 and lands, meanwhile the F9 also tests its boost-back and propulsive landing?
Attempting recovery (even if they were ready to do it on this flight) would be a bad idea. It's absolutely vital that this test is successful if the manned Dragon is to go ahead. It would be stupid to risk this by have an extra test objective.
Can't see that as even being possible. Thrust termination occurs prior to or simultaneous with LAS motor ignition and capsule separation.
Quote from: Karloss12 on 01/10/2013 09:24 pmInstead of shutting down all Merlins could they just throttle the centre engine to minimum while the Dragon clears the core and then recover the 1st stage. I expect it will involve a bit of persuading NASA that it won't affect the certification of the Dragon LAS.Why would you want to do this? It just increases the risk that the booster rams into the capsule, which is a test failure.Quote from: Karloss12 on 01/10/2013 09:24 pmAs the 1st stage wouldn't be reaching its intended altitude and speed, would the 1st stage have to launch half empty as it wouldn't have enough time to expend the fuel through the centre engine in time?Can F9 launch on half a tank?Sure, but again, what's the point of testing if you're going to perform the test in conditions that are guaranteed NOT to match an actual abort?
Instead of shutting down all Merlins could they just throttle the centre engine to minimum while the Dragon clears the core and then recover the 1st stage. I expect it will involve a bit of persuading NASA that it won't affect the certification of the Dragon LAS.
As the 1st stage wouldn't be reaching its intended altitude and speed, would the 1st stage have to launch half empty as it wouldn't have enough time to expend the fuel through the centre engine in time?Can F9 launch on half a tank?
Quote from: douglas100 on 01/10/2013 09:58 pmAttempting recovery (even if they were ready to do it on this flight) would be a bad idea. It's absolutely vital that this test is successful if the manned Dragon is to go ahead. It would be stupid to risk this by have an extra test objective. Really? Even if the first stage has propelled the Dragon to the required altitude and velocity, separated and has nothing else to do for the abort test?
Agreed that re-uasability isn't the main objective of an in flight abort test and perhaps you're right the vehicle will be destroyed by the RSO but if it is not a danger to others and does not break up, it could have a useful purpose before crashing into the Atlantic.
I doubt that any payload atop the second stage nestled inside the trunk barrel would survive a transonic abort because of the dynamic pressure. Air would rush into the trunk barrel after the capsule separates and almost certainly destroy any satellite residing there.
As for first stage RTLS, the transonic abort would occur at a significantly lower altitude than upper stage separation on the nominal flight trajectory. I doubt that the first stage structure would survive the flip to retrograde at that altitude. They need to get the first stage up and out of the sensible atmosphere to do the boost-back maneuver. And they can't just keep burning the stage because they need to demonstrate first stage shutdown as part of the abort demonstration.
Can F9 launch on half a tank?
It would be stupid to risk this by have an extra test objective.
environmental impact factors...fueled second stage crash into the Atlantic,...what about all the RP-1?
QuoteThe actual pad abort test itself will take place in December, resulting in a full-up Falcon 9 and Dragon being integrated on the Cape Canaveral launch site, prior to aborting the Dragon from the pad for a full test.This seems strange. Why demonstrate pad abort off of an otherwise perfectly good Falcon? Haven't all previous pad abort demos been done from the ground, there-by not risking damage to flight / GSE hardware?
The actual pad abort test itself will take place in December, resulting in a full-up Falcon 9 and Dragon being integrated on the Cape Canaveral launch site, prior to aborting the Dragon from the pad for a full test.
Quote from: oiorionsbelt on 01/10/2013 10:47 pmAgreed that re-uasability isn't the main objective of an in flight abort test and perhaps you're right the vehicle will be destroyed by the RSO but if it is not a danger to others and does not break up, it could have a useful purpose before crashing into the Atlantic.Yes, like demonstrating the RSO's "Big Red Button".KISS!Remember that one of the big issues for Ares-1 was that the Orion parachutes were not assured of surviving the environment anticipated after the destruction of the first stage? A full up test has to be full up.
Going over the video again, the big G never said that Dragon would be on a Falcon 9 for the pad abort, only that Dragon would be close to the final design and would demonstrate the abort capability off LC-40, they might just fire the Capsule itself off the pad.
...opportunity to demonstrate 9-engine re-start. Isn't the merlin 1D supposed to be able to do that?